The patch titled
cgroup files: turn attach_task_by_pid directly into a cgroup write handler
has been added to the -mm tree. Its filename is
cgroup-files-turn-attach_task_by_pid-directly-into-a-cgroup-write-handler.patch
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------------------------------------------------------
Subject: cgroup files: turn attach_task_by_pid directly into a cgroup write handler
From: Paul Menage <menage@xxxxxxxxxx>
This patch changes attach_task_by_pid() to take a u64 rather than a
string; as a result it can be called directly as a control groups
write_u64 handler, and cgroup_common_file_write() can be removed.
Signed-off-by: Paul Menage <menage@xxxxxxxxxx>
Cc: Paul Jackson <pj@xxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Serge Hallyn <serue@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 80 ++++++++--------------------------------------
1 file changed, 14 insertions(+), 66 deletions(-)
diff -puN kernel/cgroup.c~cgroup-files-turn-attach_task_by_pid-directly-into-a-cgroup-write-handler kernel/cgroup.c
--- a/kernel/cgroup.c~cgroup-files-turn-attach_task_by_pid-directly-into-a-cgroup-write-handler
+++ a/kernel/cgroup.c
@@ -504,10 +504,6 @@ static struct css_set *find_css_set(
* knows that the cgroup won't be removed, as cgroup_rmdir()
* needs that mutex.
*
- * The cgroup_common_file_write handler for operations that modify
- * the cgroup hierarchy holds cgroup_mutex across the entire operation,
- * single threading all such cgroup modifications across the system.
- *
* The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't
* (usually) take cgroup_mutex. These are the two most performance
* critical pieces of code here. The exception occurs on cgroup_exit(),
@@ -1279,18 +1275,14 @@ int cgroup_attach_task(struct cgroup *cg
}
/*
- * Attach task with pid 'pid' to cgroup 'cgrp'. Call with
- * cgroup_mutex, may take task_lock of task
+ * Attach task with pid 'pid' to cgroup 'cgrp'. Call with cgroup_mutex
+ * held. May take task_lock of task
*/
-static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf)
+static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
{
- pid_t pid;
struct task_struct *tsk;
int ret;
- if (sscanf(pidbuf, "%d", &pid) != 1)
- return -EIO;
-
if (pid) {
rcu_read_lock();
tsk = find_task_by_vpid(pid);
@@ -1316,6 +1308,16 @@ static int attach_task_by_pid(struct cgr
return ret;
}
+static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid)
+{
+ int ret;
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+ ret = attach_task_by_pid(cgrp, pid);
+ cgroup_unlock();
+ return ret;
+}
+
/* The various types of files and directories in a cgroup file system */
enum cgroup_filetype {
FILE_ROOT,
@@ -1431,60 +1433,6 @@ static ssize_t cgroup_write_string(struc
return retval;
}
-static ssize_t cgroup_common_file_write(struct cgroup *cgrp,
- struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
-{
- enum cgroup_filetype type = cft->private;
- char *buffer;
- int retval = 0;
-
- if (nbytes >= PATH_MAX)
- return -E2BIG;
-
- /* +1 for nul-terminator */
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (buffer == NULL)
- return -ENOMEM;
-
- if (copy_from_user(buffer, userbuf, nbytes)) {
- retval = -EFAULT;
- goto out1;
- }
- buffer[nbytes] = 0; /* nul-terminate */
- strstrip(buffer); /* strip -just- trailing whitespace */
-
- mutex_lock(&cgroup_mutex);
-
- /*
- * This was already checked for in cgroup_file_write(), but
- * check again now we're holding cgroup_mutex.
- */
- if (cgroup_is_removed(cgrp)) {
- retval = -ENODEV;
- goto out2;
- }
-
- switch (type) {
- case FILE_TASKLIST:
- retval = attach_task_by_pid(cgrp, buffer);
- break;
- default:
- retval = -EINVAL;
- goto out2;
- }
-
- if (retval == 0)
- retval = nbytes;
-out2:
- mutex_unlock(&cgroup_mutex);
-out1:
- kfree(buffer);
- return retval;
-}
-
static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
size_t nbytes, loff_t *ppos)
{
@@ -2262,7 +2210,7 @@ static struct cftype files[] = {
.name = "tasks",
.open = cgroup_tasks_open,
.read = cgroup_tasks_read,
- .write = cgroup_common_file_write,
+ .write_u64 = cgroup_tasks_write,
.release = cgroup_tasks_release,
.private = FILE_TASKLIST,
},
_
Patches currently in -mm which might be from menage@xxxxxxxxxx are
call_usermodehelper-increase-reliability.patch
cgroup-use-read-lock-to-guard-find_existing_css_set.patch
mark-res_counter_charge_locked-with-__must_check.patch
cgroup-list_for_each-cleanup-v2.patch
cgroup-anotate-two-variables-with-__read_mostly.patch
cgroup-files-clean-up-whitespace-in-struct-cftype.patch
cgroup-files-add-write_string-cgroup-control-file-method.patch
cgroup-files-move-the-release_agent-file-to-use-typed-handlers.patch
cgroup-files-move-notify_on_release-file-to-separate-write-handler.patch
cgroup-files-turn-attach_task_by_pid-directly-into-a-cgroup-write-handler.patch
cgroup-files-remove-cpuset_common_file_write.patch
cgroup-files-convert-devcgroup_access_write-into-a-cgroup-write_string-handler.patch
cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler.patch
memcg-remove-refcnt-from-page_cgroup.patch
memcg-remove-refcnt-from-page_cgroup-fix.patch
memcg-remove-refcnt-from-page_cgroup-fix-2.patch
memcg-handle-swap-cache.patch
memcg-handle-swap-cache-fix.patch
memcg-helper-function-for-relcaim-from-shmem.patch
memcg-add-hints-for-branch.patch
memcg-remove-a-redundant-check.patch
memrlimit-add-memrlimit-controller-documentation.patch
memrlimit-setup-the-memrlimit-controller.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch
memrlimit-add-memrlimit-controller-accounting-and-control.patch
memrlimit-setup-the-memrlimit-controller-cgroup-files-convert-res_counter_write-to-be-a-cgroups-write_string-handler-memrlimitcgroup.patch
cpusets-update-tasks-cpus_allowed-and-mems_allowed-after-cpu-node-offline-online.patch
make-cgroup_seqfile_release-static.patch
add-a-refcount-check-in-dput.patch
--
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